Boiler



G. W. TROTTER BOILER Jan. 19, 1937.

Filed March 17, 1934 Patented Jan. 19, 1937 PATENT orrier.

BOILER George Wilfrid Trotter,

Application March 17,

West Hartlepool, England 1934, Serial No. 716,150

In Great Britain March 25, 1933 2 Claims.

I have filed an application in Great Britain No. 9104/33 filed the 25thday of March 1933.

The present invention relates to boilers, and I particularly towater-heating boilers suitable for domestic uses such as the heating ofbuildings and greenhouses.

Objects of my invention are the utilization of the heating fuel to thehighest degree, the maintenance of combustion of the fuel at all timesso long as an adequate supply of fuel is furnished the fire box orcombustion chamber, the need for the minimum attention to the boiler tokeep it in operation, and the attainment of these objects by a structureof simple form, and compactness and one which will enable ash andclinker to be easily removed.

My invention consists in whatever is described by or is included withinthe terms or scope of the appended claims.

Fig. 1 is a longitudinal section through a boiler constructed inaccordance with the invention.

Fig. 2 is a part sectional front View of Fig. 1.

Referring to the drawing, one form of boiler made in accordance with thepresent invention comprises a firebox-casing I' having a forwardlyinclined front wall and provided with horizontal and inclined firebarsforming grates 2, 3, which are hereinafter called the bottom and thefront grate respectively. The casing I is provided in its rear part witha water heating unit comprising upper and lower transverse tubes orwater drums 4, 5, the upper drums 4 being arranged in a horizontal line,with the last one in pro-X- imity to the lower end of the flue 6, andthe lower 1 drums 5 being arranged in an inclined line with the firstone adjacent to the rear edge of the bottom grate 2. The two sets ofdrums 4, 5, are each interconnected by five spaced water tubes 1 andalso by two water jackets 8, one of which is arranged at one end of thetwo sets of water drums and the other at the opposite end thereof, andwhich constitute the side walls of the casing I. In addition, as shown,said water jackets 8 extend across the front of the boiler. As has beenindicated, the horizontal tubes or drums 4 and 5 at opposite endscommunicate with the headers or water jackets 8 that are in the oppositeside walls of the boiler and the tubes 1 which are preferably oval incross- 55 wardly inclined from their lower ends, and consectioncommunicate at their ends with the tubes sequently the front set form anapertured wall parallel with the front wall of the firebox-casing, thusaffording in conjunction therewith a forwardly inclined firebox orcombustion space 9. The inclination of this last is such that fuelentering the feeding aperture of the boiler will fall on to the inclinedfront wall and be conducted therefrom on to the bottom grate 3.

In consequence of the inclination of the firebox of combustion space andthe substantial difference in the levels of the upper portions of thespaces between the tubes 1 and the grate bars 3, a radiant surface iscontinuously maintained against the water tubes, so long as the fireboxremains full of fuel, and for the follow-' ing reasons: Assuming thatthe hopper H! and combustion space 9 are filled with fuel and thatcombustion is proceeding at full draught then the actual fire zone willslope from the bars 3 to the upper drum 4, making an acute angle withthe front wall approximately as indicated by the dotted line in Fig. 1.Now as the fuel is consumed the natural tendency of the fire is to collapse vertically downwards and to fall away from the tubes 1. There isthus a tendency for a wedge-shaped space to form next to the tubes, butas fast as this forms it is filled in by the natural rolling action ofthe fire surface and the fall of fresh fuel from the reserve above. Itwill be'seen such fresh fuel will always be supplied with hot air thathas passed through the fire zone. Consequently, it will be immediatelyignited so that a radiant surface is continuously maintained in contactwith the tubes 1.

If the fire is allowed to burn out, the wedgespace next to the tubeswill cease to be filled completely as the reserve of fuel above becomessmaller; the surface of the fire zone, however, will remain atsubstantially the same angle and the cold air will thus always have topass through the fire zone.

A very important feature of my invention lies in the fact that beforethe air supply can reach the fresh fuel, such air must pass through thefire zone. If the fresh fuel should be supplied with cold air, the firewould very soon go out. With the boiler constructed in accordance withmy invention, the combustion chamber or fire box can be filledcompletely with fuel with the assurance that it will continue to burnuntil all, or very nearly all the fuel is consumed. This result is dueto the fact, in connection with the sloping or forwardly inclined rearface of the fire box, that the uppermost portion of the passages throughthe rear side of the fire box! are substantially higher than the airinlet through the grate 3 at the bottom of front wall of the fire box.With this arrangement the line of draught is upwardly inclined at anacute angle to the front wall and consequently, the upper surface of thefire zone is correspondingly inclined. If the air inlets in the frontwall were as high as the apertures in the rear wall, the line of draughtwould run horizontally across the combustion chamber and the fuel wouldtend to fall vertically so that as soon as: the fire settled a layer offresh fuel would be formed within the line of draught and this fuelwould not ignite owing to the fact that the air supply would be cold.With this arrangement, thefire would very quickly go out.

The lower edge of the front grate 3 is supported only at the ends sothat a space is provided between it and the bottom grate 2 so as toallow of the ash and clinker being removed. The flue 6 in thisparticular case is arranged at the rear of the stove and a damper (notshown) is slidably arranged in the flue to control the draught passingtherethrough. A front closure member would also be provided in front ofthe bars 3 so as to control the air inlet.

A hopper I0 is positioned at the front of the boiler and directly overthe inclined fire zone 9. Said hopper l0 may be detachably mounted asshown. For this purpose its lower end is open and is made to fit in theusual feeding aperture, whilst a short distance from the lower end it isprovided with an outstanding flange II so that when fitted into thefeeding aperture the whole hopper will be firmly supported. The upperend of the hopper, on the other hand, is stepped outwardly so as tocorrespond with the diameter of the feeding aperture, and when thehopper III is in position the lid l2 normally used for the feedingaperture is placed in the top of the hopper, the same lid thus servingin both cases. It will thus be appreciated that the combustion of thefuel takes place within the space formed between the two water jackets,so that as much of the available heat as possible is utilized to heatthe water contained within the unit, and further that by reason of theinclination of the combustion space the fuel carried in the hopperautomatically replaces that consumed on the front grate, the fuelfalling onto the grate by the action of gravity.

If desired one or more further hoppers may be mounted in the recessedupper portion of the one already in position.

The side and rear walls of the firebox are extended beyond the bottomgrate, so that the lower edges of said walls may serve as feet for theboiler and form an ashpit. If desired, means such as an inclined baflleplate may be provided to assist in controlling the flow of fuel from thehopper to the front grate as aforesaid.

I claim:-

1. A boiler for coke and like fuels of small volatile content, having afire box or combustion space with a fuel inlet to its upper end, saidfire box or combustion space having forwardly inclined rear and frontwalls of rectilinear form in side elevation whereby the fire box becomesforwardly inclined as a whole, the rear wall being contiguous to saidinlet and afforded by inclined water tubes spaced apart to formapertures for the passage of the hot gases from the fire box to theuptake and constituting the main surface to be heated, and the frontwall being provided at the bottom with an air admitting opening of suchsize and extent that the line of draught through the fire box isupwardly inclined at an acute angle to the front wall and in a directionapproaching the vertical, the angle between the front wall and thebottom grate being approximately vertically below the topmost outletaperture in the rear wall, the whole being so arranged that fuel ismaintained in contact with the entire rear wall so long as the supply offuel is maintained.

2. A boiler for coke and like fuels of small volatile content, having afire box or combustion space with a hopper and fuel inlet to its upperend arranged to permit the unimpeded vertical entry of fuel over thefull area of said upper end, said fire box or combustion space havingforwardly inclined rear and front walls of rectilinear form in sideelevation whereby the fire box becomes forwardly inclined as a whole,the rear wall being afforded by inclined water tubes spaced apart toform apertures for the passage of the hot gases from the fire box to theuptake and constituting the main surface to be heated, and the frontwall being provided at the bottom with an air admitting opening of suchsize and extent that the line of draught through the fire box isupwardly inclined at an acute angle to the front wall and in a directionapproaching the vertical, the angle between the front wall and bottomgrate being approximately vertically below the topmost outlet aperturein the rear wall, the whole being so arranged that fuel is maintained incontact with the entire rear wall so long as the supply of fuel ismaintained.

G. W. TRO'ITER.

